alert dns $HOME_NET any -> any any (msg:"ET MALWARE Anchor_DNS stickseed Variant CnC Checkin"; dns.query; content:"efkezwpdxpsq3l"; startswith; fast_pattern; pcre:"/\.[dghbcijklmnfqrwxyz23stuopaev4569]{26}\.[a-z0-9_-]{1,50}\.[a-z]{2,8}$/"; classtype:command-and-control; sid:2033420; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, created_at 2021_07_26, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_07_26, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)